PHENOLOGY OF FLOWERING AND FRUITING OF CACTUS PEAR AND EFFECT OF NP FERTILIZING

The aim of this work was to study the phenology of flowering and fruiting of cactus pear and effect of NP fertilizing. Treatments of fertilization used are (in kg/ha): T1: 0N-0P, T2: 0N-80P, T3: 40N-40P, T4: 60N-0P and T5: 60N-80P. They are applied in April 2011 and February 2012. Obtained results showed that in the first year (2011) the emission and formation period of buds is for 98 to 104 days long (11/03 to 23/06/2011). Buds emission and formation is important in April due to favorable climatic conditions (rain field, temperature, day length and sun). The emission of shoots is 69 to 103 days long, it’s important in June when it’s higher in T5 (0.22 shoots/pad) than in the other treatments (0.075 shoots/pad or less) due to N fertilizer. Chemical analysis of soil and pads tissue showed that the content of soil and pads tissue in N is higher after harvesting fruits (18 ppm and 2.24% respectively in soil and pads tissue) than before the application of fertilizers (13,5 ppm and 1.75% respectively in soil and pads tissue). The low content of P in soil (<10 mg/kg) and the high N/P ratio in pads tissue contributed also to the emission of shoots. Flowering period is for 68 to 80 days long and fruit maturation period is for 52 to 81 days long and fertilization has no effect on these factors. Fruit development period (FDP) (137 to 152 day) is longer than that of cultivars with long FDP in South Africa (148 days) and even longer than the FDP of the majority of cultivars in this country (120 to 130 days). In the second year (2012), the periods of phenological aspects are earlier and shorter than in 2011 due to climatic conditions (high temperatures, much sun and the lack of rain in spring), what involved an earlier period of formation of floral buds and than a longer FDP (188 days) than in 2011. Fertilization has a significant effect on the emission of buds and shoots.